Your first closed terrarium: a no-fail setup guide

Closed terrariums are the closest thing to “set it and forget it” in the plant world. Build it right once, and a closed jar can thrive for years with almost zero maintenance. This guide walks you through the whole process — what to buy, how to layer it, what plants to start with.

What you’ll need

Tools (one-time buy, ~$20 total)

• A long spoon (for substrate work)
• A spray bottle (for misting)
• Tweezers or long chopsticks (for placing plants)
• A clean cloth
• Scissors (for trimming moss and roots)

Container

A clear glass container with a lid. Best beginners:

• Mason jar — cheap, easy to find, perfect first build
• Glass jar with cork lid — aesthetic, breathable, good for plants that hate wet feet
• IKEA 365+ jar — bigger, more room to play

Avoid: Anything with a narrow neck (you can’t fit your hand in to fix mistakes later). Anything plastic (scratches, doesn’t look as good).

Drainage layer

• Lava rock (best — light, porous, doesn’t compact)
• Leca / hydroballs
• Pebbles (works, but heavier and compacts over time)

Skip the activated charcoal for now. We explain why here.

Substrate

A mix of:

• Potting soil (peat-based, no fertilizer)
• Orchid bark (drainage)
• Worm castings (gentle nutrients, optional)

A simple 2:1:1 ratio works for most builds.

Plants (the part that matters most)

For your first build, use only these — they’re proven closed-terrarium survivors:

• Fittonia (nerve plant) — colorful, loves humidity, slow grower
• Pilea glauca — tiny round leaves, fills in fast
• Selaginella — moss-like, loves humidity
• Small ferns (maidenhair, button fern) — slow but beautiful
• Peperomia (small varieties) — durable, varied colors
• Sheet moss or cushion moss — ground cover

Skip for now: Succulents, cacti, anything labeled “drought tolerant.”

Moss

At least one variety of sheet or cushion moss. See our moss guide.

The 5 layers (in order)

Layer 1: Drainage (1–2 inches)

Pour lava rock or pebbles into the bottom of your container. This is where excess water will sit without touching the roots.

Layer 2: Barrier (optional but recommended)

A piece of mesh or landscape fabric cut to size, sitting on top of the drainage. This stops soil from sinking down and clogging your drainage layer.

If you don’t have mesh, a thin layer of sphagnum moss works the same way.

Layer 3: Substrate (2–3 inches)

Pre-moisten your substrate mix in a separate bowl until it’s damp but not dripping. Add to the jar and shape it: hills on the sides, valley in the middle is the classic look. Slope it forward so you can see everything through the glass.

Layer 4: Hardscape

Driftwood, rocks, bark. Position these before plants — they’re the bones of your build. A good rule of thumb: the rule of thirds. Avoid symmetry.

Layer 5: Plants and moss

Plant the biggest plants first. Use tweezers to position small ones. End with moss as the “ground cover” — fill gaps, soften edges, hide the substrate.

Final touches

• Mist lightly with distilled water
• Wipe the inside of the glass with a cloth
• Put the lid on
• Place in indirect light

The first 4 weeks

This is where most beginners panic. Don’t.

Week 1: Foggy is normal

Your jar will fog up. Condensation is good — it means the water cycle is working. If the fog is so thick you can’t see in, leave the lid off for a few hours.

Week 2: Settling

Plants may look slightly droopy as they acclimate. Some leaves may yellow and drop. This is normal transplant shock. Leave them — the dead leaves will break down and feed the system.

Week 3: First signs of growth

If plants are pushing out new leaves, you’re winning. If they’re still droopy, double- check the diagnosis flowchart in why your moss is browning.

Week 4: The equilibrium

By now, the jar should have found its balance: condensation during the day, clearing by evening. No need to water. No need to fertilize. Just observe.

Maintenance schedule

For the life of the terrarium:

• Daily: Look at it. Enjoy it. That’s it.
• Weekly: Wipe outside glass. Rotate 180° so plants grow evenly.
• Monthly: Trim anything overgrown. Open lid for 30 min if foggy.
• Quarterly: Check for mold. Add springtails if you see any fuzzy white growth.
• Yearly: Maybe add a little distilled water if the substrate is pulling from the glass.

Common first-build mistakes

1. Too many plants. A crowded jar looks bad and competes for resources. Start with 3–5 plants.
2. Wrong plants. Succulents in a closed jar is the #1 newbie mistake. They rot.
3. No drainage layer. Skip this and your roots will sit in water.
4. Direct sunlight. This cooks the jar. Indirect light only.
5. Over-misting. A closed jar needs almost no water added. If you’re misting daily, you’re doing too much.

Cost breakdown

Item	Cost	Notes
Mason jar	$2	Or use one you already have
Lava rock (small bag)	$5	Lasts 5+ builds
Substrate mix	$5	Lasts 3+ builds
Plants (3 small)	$10	Try Etsy, local nurseries
Moss	$5	Small bag
Total	~$27	Reusable: ~$15

What to do after this guide

Once your first closed jar is stable (4–6 weeks), try:

• An open terrarium with succulents (different skill set)
• A bioactive build with springtails and isopods
• A larger statement piece in a 5-gallon jar

Browse our care guides when you’re ready for the next step.

Questions? The Discord is the place. Show us your build — we’d love to see it. 🌿